It is proposed to study the nature of specific binding sites in antitumor-antibiotic DNA complexes. Circular dichroism spectra of 13 native and synthetic DNAs with known first-neighbor frequencies will be measured in the absence and in the presence of the antitumor agent. It is expected that, through the use of a simple matrix equation, the nature of the base or bases to which the antitumor antibiotic is bound can be deduced. All calculations will be done using existing computer programs.